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The aim of this study is to identify the optimal design parameters of a fully solar-powered adsorption cooling system for residential buildings located in hot arid areas. The proposed system consists of solar collectors, hot water tank, watersilica gel adsorption chiller of 8 kW cooling capacity, cold water tank, fan coil unit, and cooling tower. An optimization based on computer simulation has been conducted for achieving the aim of this study. The proposed system was applied to Assiut, Egypt as a case study. The optimization shows that the optimal design parameters of the proposed system are as follows: 58 m 2 solar collecting area, 5.5 m 3 hot water tank and 1 m 3 cold water tank. The simulation of the proposed system with the optimal design parameters during the design day shows that the chilled water temperature leaving the chiller is between 17 and 18 °C with high cooling water temperature of 34.5 °C. This makes the system unable to achieve the indoor thermal design conditions. However, the system is able to meet the cooling demand in most days of the cooling season except for about 9.15% representing extreme hot days. The simulation also shows that during the design day, the proposed system achieves daily solar collecting efficiency of 56% and can produce chilling energy of 113.3 kWh with 7.35 kW energy rate and daily COP of 0.41. In addition, the cold water tank enables the system to extend the operation period for 110 min after switching off the chiller.

Objective To evaluate the safety and efficacy of ultrasound (US) as alternative to fluoroscopy for guidance of ureteroscopy (URS) during treatment of distal ureteric stones in adults. Materials and methods This study enrolled 80 patients older than 18 years presented with a single distal ureteric radio-opaque stone of ≤15 mm in longest diameter. Patients were randomized and allocated into two groups: the fluoroscopy group and the ultrasound group (n = 40 patients in each group). Patients with bilateral ureteric stones, solitary kidney, ureteric congenital anomalies, history of failed ureteroscopy, history of ureteric surgery, patients with uremia and pregnant women were excluded. Patients’ demographics, stone characteristics, operative data, stone-free status, hospital stay and complications were evaluated in both groups. Results No statistically significant difference between both groups was found regarding patients’ demographics and stone characteristics. Also there was no statistically significant difference in comparing fluoroscopy group versus ultrasound group regarding operative time (29.48 ± 15.3 versus 31.28 ± 18.24 min; P = 0.83), stone-free rate (97.5% versus 95%; P = 1.0), overall complications (15% versus 12.5%; P = 0.75), or hospital stay (1.17 ± 0.6 versus 1.02 ± 0.16 days; P = 0.12). Four patients (10%) in the ultrasound group required the addition of fluoroscopy beside ultrasound. Conclusion Ultrasound is effective in guidance during ureteroscopy for distal ureteric stones. It was comparable to fluoroscopy in terms of stone free rate, operative time, overall complications, and hospital stay. However, fluoroscopy must be available to be used when needed.